This invention relates generally to closed loop vapor compression refrigeration systems. In particular, the invention relates to such a system that has an installed indicator to show the presence of acid contamination in the refrigerant contained in the system.
Vapor compression refrigeration systems are used both to cool and heat enclosed spaces. Typical examples of such systems are refrigerators and air conditioning, including heat pump, systems. The refrigerant in a vapor compression refrigeration system may contain acid contaminants. When a refrigerant is subjected to excessive temperatures, such as in an overheating compressor, it may decompose chemically. Commonly, one or more types of acid are found among the decomposition products, regardless of the type of refrigerant. The decomposition products of oil, varnish, insulation, gaskets and adhesives may also include acids. Not only can acids damage system components, their presence in the refrigerant can indicate component failure or imminent failure.
To assure efficient system operation as well as to detect and prevent damage, it is desirable to have a capability to determine the presence of acid contamination and, if present, remove the acid from the system.
U.S. Pat. No. 4,923,806, issued 8 May 1990 to Klowdowski, describes and claims an invention having the same assignee as the present invention. The '806 patent describes a refrigerant testing apparatus that includes a testing tube that is capable of detecting the presence and concentration of inorganic acid as well as water vapor in a stream of refrigerant vapor passing through the tube. The '806 testing apparatus also includes a testing tube holder having provisions to place the testing tube in flow communication with the refrigerant in a refrigeration system. The testing apparatus, marketed by the assignee as the TOTALTEST.RTM. refrigerant testing system, has enjoyed wide acceptance and commercial success.
Another patent, U.S. Pat. No. 5,071,768, issued 10 Dec. 1991 to Klowdowski describes and claims an invention having the same assignee as the present invention. The '768 patent describes another refrigerant testing tube having a different configuration than the '806 tube and that is not only capable of detecting the presence and concentration of both water vapor and inorganic acid in a refrigerant vapor stream but also can detect the presence of other refrigerant contaminants as well.
Both of the patents cited above describe apparatus that are separate from a refrigeration system. The apparatus must be connected to the system specifically to perform a test for refrigerant contamination and then disconnected from the system at the completion of the test. Apparatus of this type can provide useful information but do not allow for continuous monitoring of a system for contamination.
What is needed is a refrigeration system having an acid indicator that is permanently or semipermanently mounted in the system so that the refrigerant in the system can be continually monitored without removing refrigerant from the system.